Plastic fins for archery arrows

ABSTRACT

A PLASTIC GUIDE FIN FOR ARCHERY ARROWS, THE EDGE SURFACE OF SAID FIN ADAPTED TO BE SECURED STO THE ARROW SHANK BY GLUING BEING SHAPED LIKE A FOOT HAVING NARROWLY SPACED NOTCHES TO PROVIDE A PENETRATION OF GLUE THERETHROUGH AND AN EMBEDDING OF THE FOOT PORTIONS THEREBETWEEN WHEREBY A MECHANICAL GLUE JOINT IS OBTAINED.

June 6, 1972 B. R. BENGTSSON 3,667,758

PLASTIC FINS FOR ARCHERY ARROWS Filed Aug. 6, 1970 United States PatentO 3,667,758 PLASTIC FINS FOR ARCHERY ARROWS Bjorn R. Bengtsson, Box 71,S-124 21 Bandhagen 1, Sweden Filed Aug. 6, 1970, Ser. No. 61,697 Claimspriority, application Sweden, Aug. 7, 1969, 11,009/ 69 Int. Cl. F41b5/02 US. Cl. 273106.5 C 1 Claim ABSTRACT OF THE DISCLOSURE A plasticguide fin for archery arrows, the edge surface of said fin adapted to besecured to the arrow shank by gluing being shaped like a foot havingnarrowly spaced notches to provide a penetration of glue therethroughand an embedding of the foot portions therebetween whereby a mechanicalglue joint is obtained.

BACKGROUND OF THE INVENTION The present invention relates to arrows forarchery and particularly the shape of the mounting surface of the guidefins or vanes which are to be secured to the arrow shaft by means ofgluing.

Prior art fins in archery arrows have been made of natural feathersmostly from turkey, but even if impregnated such feathers have badcharacteristics as to moisture resistance, uniformity of thickness andstiffness etc. There has thus long been a demand for a plastic fietchingthat would surpass such natural feathers. The plastic fins or vaneswhich have been produced so far can be divided into :two main groupsviz:

(1) Vanes made of relatively stiff or hard, chemically soluble plastics(mainly cellulose plastics) that are glued to the arrow shaft by meansof adhesives containing proper solvents, and

(2) vanes of pliable, chemically insoluble plastics (mainly polyolefinplastics) or only slightly soluble plastics, that can only be glued bymeans of pressure-sensitive binders.

Such plastic fins, however, have a number of drawbacks. The disadvantageof the type 1) plastic vanes is their rigidness. With only a slightshooting error, the fietching often touches the bow and/or the arrowrest. When this occurs, the rigid fietching of this plastic kind causesa greater deviation in the flight of the arrow than with a fietching ofnautral feathers or sufficiently flexible plastic vanes. Attemtps havebeen made to produce sufiiciently flexible vanes of highly softenedcellulose plastics but the poor mechanical properties of these materialsrender them unsuitable for the purpose. Similar attempts have been madewith vinyl plastics and various elastomers but without satisfactoryresults.

The major disadvantage of the type (2) plastic vanes is that they cannotbe glued satisfactorily. The vanes thus loosen from the arrow shaft tooreadily during shooting and upon impact with the target.

3,667,758 Patented June 6, 1972 The main object of the present inventionis to provide an archery arrow vane having a mounting surface of a shapethat will secure a greatly improved glue attachment to the arrow shank.This object is achieved by the feature that the edge surface of said finor vane, which is adapted to be secured to the arrow shank, is shapedlike a rib-like foot extending laterally to both sides of said fin andhaving narrowly spaced notches adapted to provide a penetration of gluetherethrough and a partial or total embedding of the foot portionsbetween the notches, whereby a mechanical glue joint is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS By way of example, the invention willbe further described below by referring to the accompanying drawings, inwhich FIG. 1 is a side elevational view of a fin according to theinvention mounted on the shank of an archery arrow,

FIG. 2 is a cross-sectional view of the fin according to FIG. 1 takensubstantially along the line IIII, and

FIG. 3 is a plan view of the same fin.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings,a section of an arrow shank 1 is illustrated having mounted thereon aguide fin or vane 2 of suitable contour. Said fin is made of a plasticmaterial, preferably a polyamide material such as Polyamide 11 or Nylon11. Although said fin 2 has been illustrated as being non-apertured inthe drawings, it can of course be provided with suitable apertures inthe form of slots, rows of holes etc., as required for aerodynamicalpurposes.

According to the invention, on its mounting edge the fin is shaped likea rib-like foot generally designated 3. More especially, said foot 3 isextended laterally to both sides of said fin and provided with narrowlyspaced notches 4, leaving therebetween foot portions 5. Owing to saidnotches, when said fin 2 is to be mounted to the arrow shank 1 having alayer of suitable glue disposed thereupon, said glue will penetrate frombelow through said notches 4 to provide a partial or total embedding ofthe foot portions 5, whereby a mechanical glue joint is obtained.

In connection with the polyamide material used for the fin, it hasturned out to be most suitable to utilize a glue of a nitrile rubbertype, but of course also other glues might be used provided only thatthey exhibit the proper Shore hardness.

In order to further improve the glue attachment of the fin or vane 2 tothe arrow shank, according to a preferred embodiment of the inventionthe notches are formed wider, as seen longitudinally of said arrow,adjacent their base at the fin proper and narrower at their portionremotest from the fin, so that the foot portions 5 lying therebetweenbecome shaped narrowing from their outer extremity towards the fin, asseen in plan view.

Although the invention has been described above as applied to somepreferred embodiments, it is evident that also a number of modificationsand alterations can be made by those skilled in the art.

3,667,758 7 3 What I claim is: r r r in shape from their outer extremitytowards the fin, as 1. A plastic guide fin for archery arrows, the edgesurseen in plan view. face of said fin adapted to be secured to thearrow shank by gluing being shaped like a rib-like foot, said foot ex-References Cited tending laterally to both sides of said fin and having5 UNITED STATES PATENTS narrowly spaced notches adapted to provide whengluing 1,172,396 6 SChlieder 164111 X said fin to the arrow shank, apenetration of glue there- 3,519,524 7/ 0 Baumbach 156----304 X throughand at least a partial embedding of the foot por- FOREIGN PATENTS tionsbetween said notches whereby a mechanical glue 10 814,439 1959 GreatBritain.

joint is obtained, said notches being wider, as seen lon- 9,591 1901Great Britain gitudinally of said arrow, adjacent their base at the finproper and narrower at their portion remotest from the RICHARD K PYlmafYfl fin, so that the foot portions lying therebetween narrow 15 P. E.SHAPIRO, Assistant Examiner 3

